Musnad Ahmad Hadith 280

‘Umar said to me: Haven`t I been told that you do certain tasks for the state, then when you are given payment you do not accept it? He said: Yes. He said: Why do you do that? He said: I am well off and I have slaves and horses; I want my work to be a charity to the Muslims. He said: Do not do that, for I used to do what you are doing, and the Messenger of Allah (ﷺ) would give me payment, and I would say: Give it someone who is more in need of it than me, And he said: Whatever of this wealth comes to you when you are not hoping for it or asking for it, take it, otherwise do not hanker after it.” It was narrated that as-Sa`ib bin Yazeed said: `Umar met `Abdullah bin as-Sa`di... and he mentioned a similar report, but he said: “Give it in charity,” and he said: “Do not hanker after it.`